Well. I'm back with a followup. While I had the gas tank out (105,000 miles) I replaced the fuel pump and sending unit. Didn't think that was the problem but what the heck. I was right, it didn't fix it. Removed the cluster panel and replaced the stepping motor on the back of the fuel gage and bingo. I now have a functional gas gage. For a good procedure on removal of the cluster gage google HOW TO REMOVE RENDEZVOUS INSTRUMENT CLUSTER. Select the Buick forum link. Youtube has a good procedure on replacing the stepping motor on the cluster panel. Geed luck all.